The Google Stadia app is available in the store ... but you will not be able to do anything with

Expected for mid-November, Google Stadia is already a reality on Android, with the immediate availability of the application.

Good news for anyone eager to test Google Stadia! The application is now downloadable via the Android PlayStore.

A downloadable app but ... useless

The bad news is that the latter is not used at the moment for anything ... If not take a few days in advance, before seeing the official landing of the service.

Once you've installed the app, you can select your Google Account, which will display a new screen that prompts you to enter your Google Stadia activation code. A code that will not be sent until November 19, at the earliest. Still a little patience, then.
Source: AndroidPolice